Male and female patients of Dr. William Jennings and Dr. Pranay Kathuria undergoing dialysis therapy as outpatients. Dialysis and pre-dialysis patients will be recruited from Dr. Pranay Kathuria's practice. Normal volunteers will be recruited from family members of the pre-dialysis patients, Internal Medicine patients already scheduled to have blood drawn for other reasons, or from faculty/staff/student volunteers who are not otherwise involved with the study and are not in a subordinate role to any of the study investigators.